A....add a dot of 2 going left. and for 7 put a dot at the 7 goes right.
B... put a dot on 2 then make a arrow going right and for 7 put a dot going left.
Answer: 
Step-by-step explanation:

a=2
b=-9
c=5





Answer:
4n+13
Step-by-step explanation:
combine like terms.